Merge pull request #8781 from rst0git/cr-volumes

Add support for checkpoint/restore of containers with volumes

2 files changed, 81 insertions, 9 deletions

diff --git a/libpod/container_api.go b/libpod/container_api.go
index c3e1a23d2..2c7dc79c9 100644
--- a/libpod/container_api.go
+++ b/libpod/container_api.go
@@ -703,6 +703,9 @@ type ContainerCheckpointOptions struct {
 	// important to be able to restore a container multiple
 	// times with '--import --name'.
 	IgnoreStaticMAC bool
+	// IgnoreVolumes tells the API to not export or not to import
+	// the content of volumes associated with the container
+	IgnoreVolumes bool
 }
 
 // Checkpoint checkpoints a container
diff --git a/libpod/container_internal_linux.go b/libpod/container_internal_linux.go
index bc8f0f932..ac20e1f25 100644
--- a/libpod/container_internal_linux.go
+++ b/libpod/container_internal_linux.go
@@ -798,11 +798,11 @@ func (c *Container) addNamespaceContainer(g *generate.Generator, ns LinuxNS, ctr
 	return nil
 }
 
-func (c *Container) exportCheckpoint(dest string, ignoreRootfs bool) error {
-	if (len(c.config.NamedVolumes) > 0) || (len(c.Dependencies()) > 0) {
-		return errors.Errorf("Cannot export checkpoints of containers with named volumes or dependencies")
+func (c *Container) exportCheckpoint(options ContainerCheckpointOptions) error {
+	if len(c.Dependencies()) > 0 {
+		return errors.Errorf("Cannot export checkpoints of containers with dependencies")
 	}
-	logrus.Debugf("Exporting checkpoint image of container %q to %q", c.ID(), dest)
+	logrus.Debugf("Exporting checkpoint image of container %q to %q", c.ID(), options.TargetFile)
 
 	includeFiles := []string{
 		"checkpoint",
@@ -815,7 +815,7 @@ func (c *Container) exportCheckpoint(dest string, ignoreRootfs bool) error {
 	// Get root file-system changes included in the checkpoint archive
 	rootfsDiffPath := filepath.Join(c.bundlePath(), "rootfs-diff.tar")
 	deleteFilesList := filepath.Join(c.bundlePath(), "deleted.files")
-	if !ignoreRootfs {
+	if !options.IgnoreRootfs {
 		// To correctly track deleted files, let's go through the output of 'podman diff'
 		tarFiles, err := c.runtime.GetDiff("", c.ID())
 		if err != nil {
@@ -878,6 +878,47 @@ func (c *Container) exportCheckpoint(dest string, ignoreRootfs bool) error {
 		}
 	}
 
+	// Folder containing archived volumes that will be included in the export
+	expVolDir := filepath.Join(c.bundlePath(), "volumes")
+
+	// Create an archive for each volume associated with the container
+	if !options.IgnoreVolumes {
+		if err := os.MkdirAll(expVolDir, 0700); err != nil {
+			return errors.Wrapf(err, "error creating volumes export directory %q", expVolDir)
+		}
+
+		for _, v := range c.config.NamedVolumes {
+			volumeTarFilePath := filepath.Join("volumes", v.Name+".tar")
+			volumeTarFileFullPath := filepath.Join(c.bundlePath(), volumeTarFilePath)
+
+			volumeTarFile, err := os.Create(volumeTarFileFullPath)
+			if err != nil {
+				return errors.Wrapf(err, "error creating %q", volumeTarFileFullPath)
+			}
+
+			volume, err := c.runtime.GetVolume(v.Name)
+			if err != nil {
+				return err
+			}
+
+			input, err := archive.TarWithOptions(volume.MountPoint(), &archive.TarOptions{
+				Compression:      archive.Uncompressed,
+				IncludeSourceDir: true,
+			})
+			if err != nil {
+				return errors.Wrapf(err, "error reading volume directory %q", v.Dest)
+			}
+
+			_, err = io.Copy(volumeTarFile, input)
+			if err != nil {
+				return err
+			}
+			volumeTarFile.Close()
+
+			includeFiles = append(includeFiles, volumeTarFilePath)
+		}
+	}
+
 	input, err := archive.TarWithOptions(c.bundlePath(), &archive.TarOptions{
 		Compression:      archive.Gzip,
 		IncludeSourceDir: true,
@@ -888,13 +929,13 @@ func (c *Container) exportCheckpoint(dest string, ignoreRootfs bool) error {
 		return errors.Wrapf(err, "error reading checkpoint directory %q", c.ID())
 	}
 
-	outFile, err := os.Create(dest)
+	outFile, err := os.Create(options.TargetFile)
 	if err != nil {
-		return errors.Wrapf(err, "error creating checkpoint export file %q", dest)
+		return errors.Wrapf(err, "error creating checkpoint export file %q", options.TargetFile)
 	}
 	defer outFile.Close()
 
-	if err := os.Chmod(dest, 0600); err != nil {
+	if err := os.Chmod(options.TargetFile, 0600); err != nil {
 		return err
 	}
 
@@ -906,6 +947,10 @@ func (c *Container) exportCheckpoint(dest string, ignoreRootfs bool) error {
 	os.Remove(rootfsDiffPath)
 	os.Remove(deleteFilesList)
 
+	if !options.IgnoreVolumes {
+		os.RemoveAll(expVolDir)
+	}
+
 	return nil
 }
 
@@ -971,7 +1016,7 @@ func (c *Container) checkpoint(ctx context.Context, options ContainerCheckpointO
 	defer c.newContainerEvent(events.Checkpoint)
 
 	if options.TargetFile != "" {
-		if err = c.exportCheckpoint(options.TargetFile, options.IgnoreRootfs); err != nil {
+		if err = c.exportCheckpoint(options); err != nil {
 			return err
 		}
 	}
@@ -1201,6 +1246,30 @@ func (c *Container) restore(ctx context.Context, options ContainerCheckpointOpti
 		return err
 	}
 
+	// When restoring from an imported archive, allow restoring the content of volumes.
+	// Volumes are created in setupContainer()
+	if options.TargetFile != "" && !options.IgnoreVolumes {
+		for _, v := range c.config.NamedVolumes {
+			volumeFilePath := filepath.Join(c.bundlePath(), "volumes", v.Name+".tar")
+
+			volumeFile, err := os.Open(volumeFilePath)
+			if err != nil {
+				return errors.Wrapf(err, "Failed to open volume file %s", volumeFilePath)
+			}
+			defer volumeFile.Close()
+
+			volume, err := c.runtime.GetVolume(v.Name)
+			if err != nil {
+				return errors.Wrapf(err, "Failed to retrieve volume %s", v.Name)
+			}
+
+			mountPoint := volume.MountPoint()
+			if err := archive.UntarUncompressed(volumeFile, mountPoint, nil); err != nil {
+				return errors.Wrapf(err, "Failed to extract volume %s to %s", volumeFilePath, mountPoint)
+			}
+		}
+	}
+
 	// Before actually restarting the container, apply the root file-system changes
 	if !options.IgnoreRootfs {
 		rootfsDiffPath := filepath.Join(c.bundlePath(), "rootfs-diff.tar")